Adjustable hand-held tools such as wrenches and the like are well known and widely used, either in the home or in industry. The tools typically have mechanically adjustable components, which are hand-operated until a desired torque is applied to a work piece. Hand held tools require certain structural characteristics to be useful for a variety of common applications. The tools need to be ergonomically shaped and sized to permit access of the tool into restricted spaces such as on machinery. In addition, the tools need to be strong and durable to withstand normal operation conditions. Moreover, the mechanism of adjustment should be easy to operate and be able to maintain a precise adjustment. An example of such a mechanically adjustable tool is U.S. Pat. No. 4,787,275, issued Nov. 29, 1988 to Colvin for “Adjustable Doubled-Ended Box Wrench”. Disadvantageously, tools with mechanical adjustable components tend to increase the bulk of the tool, especially adjacent the tool head where accessibility is most desirable. Cavities are often disposed within the tool to house the mechanical components, which compromises the strength of the tool's handle, which is used during leveraging. Furthermore, tools with mechanical components may not allow for precise adjustability or maintenance of the adjustment once set. This is because the mechanical components have to be loose fitting in order to reduce friction and to allow the adjusting mechanism to work quickly and easily.
Thus there is a need for an improved adjustment device for a tool.